From Sonic Retro

Marine the Raccoon, as seen in the Sonic the Hedgehog Archie comics.

One of the biggest expanded universes in the world of Sonic the Hedgehog have been the various Sonic the Hedgehog comic series published in America, Great Britain and Japan, and have been part of the Sonic world from its beginning—from the establishment of the Sonic the Hedgehog manga in 1992 to the ongoing publishing of Sonic the Hedgehog and Sonic Universe, these stories have both been influenced by the game series and influenced them (a la Sonic Spinball.)

The Sonic the Hedgehog manga series, published in Shogakukan's Shogaku Yonensei (literally "fourth-year student") was written by Kenji Terada and it was illustrated by Sango Norimoto. The manga, which started in 1992, was about a hedgehog boy named Nicky who can turn into Sonic the Hedgehog. Sonic fights Eggman, with Tails tagging along to help him.

Sonic the Comic was a UK comic published by Fleetway Editions between 1993 and 2002. Labeled "The UK's official Sega comic", Sonic the Comic was one of few pieces of Sonic fiction to faithfully replicate the world of the 16-bit era video games: elements and terms from the games such as zones, rings, item boxes and star posts were incorporated into the comic. The publication's own identity and ongoing storyline and setting were established with a story in which Sonic, Tails and their friends were sent forward in time six months. During their absence, Doctor Robotnik conquered the entire planet Mobius, and Sonic's group were forced underground, operating as "freedom fighters" attempting to bring down Robotnik's rule of the planet. Due to an aggressive series of budget cuts on the part of Fleetway, the series went into full reprint by issue 184; the final story ended with a number of loose ends left untied. The comic is now unofficially being continued online.

Sonic the Hedgehog was a long-running series of American comic books published by Archie Comics from July 1993 to February 2017. All of Archie's Sonic-related series, miniseries and specials took place in the same fictional universe. This universe featured a mixture of characters, settings and situations from the video games, the SatAM cartoon, the various other incarnations of Sonic, and many elements unique to the comic universe. The entire line of comics have been cancelled as of July 19, 2017, with a new comic by IDW Publishing to come in April 2018.

Sonic X is the title of a comic book series also published by Archie Comics that exists to supplement the stories from the animated series of the same name. It began in September 2005 and was originally meant to be a four-part series; due to the positive reaction to the series' announcement, it was extended to ongoing status before the first issue premiered. The comic is unique in that it is not directly based on the games; the comic is based on the television show and takes place in its expanded fictional universe. The comic borrows elements from the series first two seasons of the show and characters from the Sonic Adventure storyline. The comic has been canceled, and its place has been taken by the new Sonic comic book series called Sonic Universe.